ORIGINAL ARTICLE Artificial Skin, Muscle, Bone / Joint, Neuron Repair of segmental radial defects in dogs using tailor-made titanium mesh cages with plates combined with calcium phosphate granules and basic fibroblast growth factor-binding ion complex gel Muneki Honnami 1,2 • Sungjin Choi 3 • I-li Liu 1 • Wataru Kamimura 4,5 • Tetsushi Taguchi 5 • Makoto Ichimura 6 • Yukinori Urushisaki 6 • Hironori Hojo 3 • Nobuyuki Shimohata 3 • Shinsuke Ohba 3 • Koichi Amaya 6 • Hiroyuki Koyama 4 • Ryohei Nishimura 1 • Ung-il Chung 2,3 • Nobuo Sasaki 1 • Manabu Mochizuki 1 Received: 15 December 2015 / Accepted: 2 July 2016 Ó The Japanese Society for Artificial Organs 2016 Abstract Repair of large segmental defects of long bones are a tremendous challenge that calls for a novel approach to supporting immediate weight bearing and bone regen- eration. This study investigated the functional and biolog- ical characteristics of a combination of a tailor-made titanium mesh cage with a plate (tTMCP) with tetrapod- shaped alpha tricalcium phosphate granules (TB) and basic fibroblast growth factor (bFGF)-binding ion complex gel (f-IC gel) to repair 20-mm segmental radial defects in dogs. The defects were created surgically in 18 adult beagle dogs and treated by implantation of tTMCPs with TB with (TB- gel group) or without (TB group) f-IC gel. Each tTMCP fitted the defect well, and all dogs could bear weight on the affected limb immediately after surgery. Dogs were euthanized 4, 8 and 24 weeks after implantation. Histo- morphometry showed greater infiltration of new vessels and higher bone union rate in the TB-gel group than in the TB group. The lamellar bone volume and mineral apposi- tion rate did not differ significantly between the groups, indicating that neovascularization may be the primary effect of f-IC gel on bone regeneration. This combination method which is tTMCP combined with TB and f-IC gel, would be useful for the treatment of segmental long bone defects. Keywords Fibroblast growth factor Á Rapid prototyping Á Segmental bone defect Á Tetrabone Ò Á Titanium mesh cage Introduction Repair of large segmental defects of long bones are a tremendous challenge in orthopedic surgery. The current treatment options include bone grafting, vascularized bone transplantation, and distraction osteogenesis. However, these techniques often require multistage surgeries including several revisions to achieve healing, demand special surgical skill, and restrict early limb function. Biocompatible prosthetic implants employing various types of artificial bones and metals have been investigated for their potential to overcome these barriers. Recently, rapid prototyping (RP) using computer-aided design/computer-aided manufacturing (CAD/CAM) pro- cedures have been used for many biomedical applications [1–4]. One RP technique, selective laser melting (SLM) of titanium alloy powders, has been used to produce cus- tomized biomedical implants for the replacement of hip and knee joints and reconstruction of mandibular defects [5–7]. & Manabu Mochizuki amm@mail.ecc.u-tokyo.ac.jp 1 Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1- 1-1Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan 2 Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan 3 Division of Clinical Biotechnology, Graduate School of Medicine, Center for Disease Biology and Integrative Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo- ku, Tokyo 113-8655, Japan 4 Division of Tissue Engineering, Department of Vascular Regeneration, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan 5 Nanoscale Materials Division, Biomaterials Unit, Smart Biomaterials Group, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan 6 Matsuura Machinery Corporation, 1-1 Urushihara-cho, Fukui 910-8530, Japan 123 J Artif Organs DOI 10.1007/s10047-016-0918-5